Researchers note that cicada populations ordinarily emerge from the soil together during one particular year and then are absent for up to 17 years. The periodical insect army last emerged in 2003.
“Overwhelming numbers” of periodical cicadas are expected to emerge from the ground this month in the US states of Virginia, West Virginia and North Carolina after being underground for 17 years, the Virginia Polytechnic Institute and State University detailed in a statement.
Experts at Virginia Tech expect the periodical cicadas, which belong to so-called Brood IX, to see as many as 1.5 million insects per acre. They noted that the natural phenomenon took place in the region about 17 years ago, although some parts of the area saw the emergence of Brood II in 2013.
“The scale of these emergence events is astounding, with as many as 1.5 million cicadas emerging per acre. Each periodical cicada brood covers a specific geographical region, with some areas overlapping,” the statement said.
Entomologists note that cicadas emerge either yearly or periodically with a 13- or 17-year interval, depending on the species.
Experts explained that the insects – which are no danger to animals and humans – do not damage plants by feeding on them, although their egg-laying habits can endanger some crops.
“Cicadas can occur in overwhelming numbers and growers in predicted areas of activity should be watchful,” said Doug Pfeiffer, a professor and extension specialist in the Department of Entomology.
The large winged insects, similar to grasshoppers, begin emerging usually in the period between mid-May and June, as they need warm weather rainfall, according to Fox 5 DC.
After recently migrating to North America, periodical cicadas are a common insect species now found on all continents except Antarctica. Generations of the insect usually do not live longer than six weeks before they mate, lay eggs and die off.
Earlier, multiple reports suggested that the United States would see the appearance of a so-called murder hornets native to tropical East Asia, South Asia, mainland Southeast Asia and portions of the Russian Far East. The large Asian wasp has recently been found in the Pacific Northwest of the US.